text: There have been attempts to reconstruct ocean paleotemperatures by chert Si isotopic record, which proposed that the Archean seawater temperatures were significantly higher than modern (~70 °C). However, subsequent studies question this palaeothermometry method and offer alternative explanation for the δSi values of Archean rocks. These signals could result from diagenetic alteration processes that overprint the original δSi values, or reflect that Archean cherts were composed of different Si sources. It is plausible that in during the Archean the dominant sources of Si sediments were weathering, erosion, silicification of clastic sediments or hydrothermal activity, in contrast to the vast SiO biomineralization in the modern ocean.